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FILE - In a Sept. 12, 2012 file photo, John O'Hara, center, of Barclays directs trading on the floor of the New York Stock Exchange, in New York. Stock futures are following global markets into negative territory for a second day Tuesday, Sept. 18, 2012 with investors again sizing up the myriad of economic challenges ahead. (AP Photo/Henny Ray Abrams, File)

FILE - In a Sept. 12, 2012 file photo, John O'Hara, center, of Barclays directs trading on the floor of the New York Stock Exchange, in New York. Stock futures are following global markets into negative territory for a second day Tuesday, Sept. 18, 2012 with investors again sizing up the myriad of economic challenges ahead. (AP Photo/Henny Ray Abrams, File)